Vehicle headlight



Patented Oct. 9,1928.

PATENT OFFICE.

VEHICLE HEADLIGHT.

WII 'JIJLAM H. WQOD, QF SOUTH EUCLID, OHIO.

Application filed May 8, 1926. Serial No. 107,582.

This invention relates to vehicle headlights and has for its object theprovision of a new and improved construction of lens which in Icombination with reflectors of a certain kind shall produce an improvedpattern and distribution of the light, especially when used with what isknown as a two filament lamp bulb. Another object of the invention isthe provision'of a combination of lens and reflector which shall havesuch cooperating parts or regions as shalldispense with the necessityfor ribbing or corrugating or moulding the glass on more than one sideof the lens. l5 The theoretically best form of light pattern has longbeen known and is characterized by a kind of semicircular or crescentshape with its straighter side lowermost and horizontal, the maximumintensity near the top so as to O afford carrying power, yet with afairly sharp (but not too sharp) out off. There should be no light abovethe horizontal except a very little at the center of the beam, but aconsiderable lateral illumination below the horizontal.

These features alone are not easy to secure but upon these has beensuperposed the double filament lamp, having two independently usablelight sources located, generally, one

above the other and designed to enable the elevation or depression ofthe beam according to whether the road ahead be deserted or occupied. Toafford the best results the shift from one filament to the other shouldserve merely to depress the beam a few degrees without change of patternor of color, but the peculiarity of a parabolic reflector is that ashift of the light source from one side of the axis to the other hasmore than a mere :0 shifting effect; it reverses the pattern, whereasthe problem is merely to shift the pattern but without reversal. Theproblem is complicated by the fact that different parts of thereflectorbehave ina much different way as regards the light source, and also thatanydisplacement of the light source from the focal point tends toproduce dark spots in the field. It should also be remembered, althoughoften forgotten, that the direct effect of the lens is comparativelysmall since more than three quarters of the light emitted by the sourcefalls first on the reflector and only one fourth or less falls directlyon the lens. It is possible to make a reflector which alone produces theeffect desired, at least substantially, but this is diflicult toaccomplish, the bulb must be. located accurately, dark' ,spots are hardto abolish, and the manufacturing and adjusting tolerance is small. Theuse of a lens which is so designed as to cooperate with the reflectorincreases this tolerance and smooths out the light beam, and is littleif any more expensive than a plain glass cover, which must always beemployed in any event to exclude the weather, provided only that it havecorrugations on one side only, for the presence of corrugations on bothsides increases the expense in a very remarkable way. Accordingly I haveproduced a combination of lens and reflector which can both be madeeasily and cheaply and used readily and with wide tolerance inmanufacturing and adjusting.

In the drawings accompanying and form ing a part of this application Ihave shown certain physical embodiments of my invention. Fig. 1 is avertical, axial sectional view through a headlight containing myimprovements; Fig. 2 is a front elevation thereof; Fig. 3 is a viewsimilar to Fig. 1 showing a modification; Fig. 4 is a front elevation ofthe headlight shown in Fig. 3; Figs. 5 and 6 are sectional viewscorresponding to the lines 5-5 and 6-6 of Figs. and 4 respectively; andFig. 7 is a front elevation of another modification. I

The reflector in each case consists of a sheet metal member 1 having asocket 2 for the reception of the lamp bulb 3. At ts two s des thereflector possesses parabohc portions A, A having a common axls a-a,WhlCh 1s substantially horizontal during the ordinary use of thereflector, and with which the socket is generally The portion of thereflector at and near the axial vertical plane, both above and below theaxis, is leaned downwardly as compared with the surface of theparaboloid if extended to those points. This produces portions B and Cwhich are shown as below the dotted line A which is in the same surfaceof revolution with A A. There is considerable lati-g tude of choice asto the exact nature of the surfaces B and C. A very satisfactoryconstruction is to employ a parabolic generator (on the vertical axialplane) with downwardly inclined axes, or they can consist of a number ofparaboloids merging together.

centered more or less accurately. I

The'reason for leaning them downwardly is to neutralize the upward glareotherwise pro- I source above or below the focal point. The- I lessdeflecting power at the regions D which.

portions B and C merge with the portions A A, and the latter may or maynot include the heel of the reflector, depending upon their relativewidth; It makes no difference as regards my invention and only a little'difference upon the light pattern provided only that thetwo surfacesmeet at some polnt behind the plane which includes the focus f of theparabola A A. The portions B, C, whether consisting of one or severalparabolas, also have their focal points close to the point 7.

When used with a double filament lamp as shown in Figs. 1 and 3 thefilaments 4 and 4 are located one above the other and substantially inthis parametral plane. I am not limited to having one filament below andone above the axis since one may be on the axis or both to one sidethereof although I prefer to have them on opposite sides but the lowerone nearer to the axis.

- It is characteristic of, this reflector that the side wings A A areused for distant lighting and the upper and lower portions for nearlighting. In order to cooperate with these requirements the lens 5 whichI provide has upright flutes over a considerable part of its surface,designed to spread the light laterally to make it cover the road. Theseflutes are made with less curvature and consequently lie in front of thereflector portions A A than at the regions E, E nearer the center. Thiscan be efl'ectedeither by making the flutes wider as shown in Figs. 2,5, and 7, while maintaining the same. depth, or making them shallower asshown in Figs. 4 and 6 while maintaining the same-width. This is fortwo.

angle of spreading is more effective than in respect of rays whichstrike the ground more quickly.

These flutes can be strictly vertical if desired as shown in Fig. 7, orcan be inclined slightly for the purpose of securing an addi tionaldlfl'using effect in a vertical plane without impairing the eflectheretofore described.

This inclination if employed at all should be in opposite directions atthe two sides of the central vertical diameter of the lens and a theamount of such inclination should be only small, e. g. from 2 to 10, sothat the spread- 1ng effect is always much greater in horizontal planethan vertically.

The ribs of smaller curvature which lie at both si'desof the grooves 9are shown at 12 and. the rim of the lens hasa flat margin 13. The

flutes or corrugations are preferably on the l inner face of the lensand the shape of this margin is preferably the sameon the inner claimis:

shown as circular in Fig. 7 and exaggeratedly non-circular in Fig 2 and4:.

I ,do not limit yself to grooves of any, specific form. They may besymmetrical or prismatic. It will be undestood that this range of choicedoes notoccur with a plain paraboloid reflector butonly with one whichis so modified as toemit the distance beam at the two side portions andthe near light and curb light at other points.

Inasmuch as the headlight has been designed to operate with twofilaments located either above or below the axis it will be understoodthat it is also valuable for use with a single filament lamp or with adouble filament lamp having one filament burned out. It will also beunderstood that with the wide tolerance in manufacture and adjustmentpermitted by my improvements it becomes possible to dispense withadjusting devices and make the lamp with fixed focus. It will also beunderstood that the portions B and C can merge into the portions A Aeither directly or by way of intermediate, transition, surfaces. Theword upright as applied to the position of the ribs includes both thestrictly vertical and the limited inclination as illustrated anddescribed. Many changes in detail can, therefore, be made within thescope 'of my invention and I do not limit myself Having thus describedmy invention what 1-. In a vehicle headlight, the combination 5 of areflector having at its two lateral portions a pair of opposedparaboloid segments whose axis is substantially horizontal, saidreflector having its upper and lower median portions leaned downwardlyas compared with the-surface of the paraboloid defined by said lateralportions, a lamp bulb located in such axis and having two independentlyusable, vertically spaced filaments, and a lens in front of saiddeflector, said lens having vertical flutes terminating coextensivelywith the translucent portion of the lens at top and bottom, thecurvature of saidflutes being less adjacent the lateral edges of thelens than at re- 2. In a vehicle 'headlight, the combination gionsnearer the top and bottom edges thereof a reflector having its twolateral portions consisting of a pair of opposed segments, of the sameparaboloid whose axis is substantially horizontal, said reflector havingits upper and lower median portions leaned downwardly as compared withthe surface of the paraboloid defined by said lateral portions, a lampsocket coaxial with such paraboloid,

and a lens having upright ribs extending from top to bottom of thelight-emitting surface and arranged in a bilaterall symmetrical mannerupon oppositesides of the central vertical diameter, the transversecurvatureaof said ribs being less in those portions of the lens whichlie in front of said paraboloid segments than in those portions of thelens which lie nearer the top and bottom edges thereof, and a lamp bulbin said socket having two independently usable vertically spacedfilaments located substantially in the same vertical line which containsthe focal point of said paraboloid.

3. In a vehicle headlight, the combination with a lamp bulb having twoindependently usable concentrated filaments located one above theother,'of a reflectorhaving at its two lateral portions a pair ofopposed paraboloid segments whose axis is substantially horizontal andwhose focal point is located I onsubstantially the same vertical linewhich contains said filaments, said reflector having its upper and lowermedian'portions leaned downwardl as compared with the surface of thepara oloid defined by said lateral porae seasea signature.

tions, and a lens having upright ribs formed v at and adjacent to thevertical axis adjacent the top and bottom margins of the translucentportion, said ribs decreasing in curvature to ward the lateral marginsof the lens.

4. 111a vehicle headlight, the combination of a reflector having its twolateralportionsat and near the horizontal plane conforming to a singleparaboloid whose axis is substanhorizontal, said reflector having itstially medlan portions leaned downwardly at a greater angle than thesurface of the paraboloid defined by said lateral portions,- and aiwoon.

